This study is designed to evaluate the safety and antiviral activity of tenofovir disoproxil
fumarate (TDF, tenofovir DF) compared to adefovir dipivoxil (ADV) for the treatment of
HBeAg-positive chronic hepatitis B. Participants will receive either TDF or the approved
hepatitis B therapy ADV. After 48 weeks all participants will be switched to open-label TDF.

Percentage of Participants With HBsAg Loss or Seroconversion to Anti-HBs at Week 96

Percentage of Participants With HBsAg Loss or Seroconversion to Anti-HBs at Weeks 144, 192, 240, 288, 336, and 384

Number of Participants With HBV Genotypic Changes From Baseline at Week 48 (Resistance Surveillance)

Number of Participants With HBV Genotypic Changes From Baseline at Week 96 (Resistance Surveillance)

Number of Participants With HBV Genotypic Changes From Baseline at Week 144 (Resistance Surveillance)

Number of Participants With HBV Genotypic Changes From Baseline at Week 192 (Resistance Surveillance)

Number of Participants With HBV Genotypic Changes From Baseline at Week 240 (Resistance Surveillance)

Number of Participants With HBV Genotypic Changes From Baseline at Week 288 (Resistance Surveillance)

Number of Participants With HBV Genotypic Changes From Baseline at Week 336 (Resistance Surveillance)

Number of Participants With HBV Genotypic Changes From Baseline at Week 384 (Resistance Surveillance)

Detailed description:
Efficacy of TDF versus ADV will be evaluated for histologic improvement, reductions in serum
HBV DNA, changes in liver enzymes, and the generation of antibody to the virus. Safety will
be assessed by evaluating adverse events, laboratory abnormalities and the development of
drug-resistant mutations. After 48 weeks, all participants will receive open-label TDF, and
the efficacy and safety of TDF will be monitored for the remainder of the study.

Eligibility

Minimum age: 18 Years.
Maximum age: 69 Years.
Gender(s): Both.

Criteria:

Inclusion Criteria:
A patient must meet all of the following inclusion criteria to be eligible for
participation in this study: